| 7000 | ÷ | ( | ( | 2000 | + | x | ) | ÷ | 2 | ) | = | 7 2 |
| 方程两边同时乘以: | ( | ( | 2000 | + | x | ) | ÷ | 2 | ) |
| 7000 | = | 7 2 | ( | ( | 2000 | + | x | ) | ÷ | 2 | ) |
| 7000 | = | 7 2 | ( | 2000 | + | x | ) | ÷ | 2 |
| 7000 | = | 7 4 | ( | 2000 | + | x | ) |
| 7000 | = | 7 4 | × | 2000 | + | 7 4 | x |
| 7000 | = | 3500 | + | 7 4 | x |
| - | 7 4 | x | = | 3500 | − | 7000 |
| - | 7 4 | x | = | - | 3500 |
| 3500 | = | 7 4 | x |
7 4 | x | = | 3500 |
| x | = | 3500 | ÷ | 7 4 |
| = | 3500 | × | 4 7 |
| = | 500 | × | 4 |
| x | = | 2000 |